1. Field of the Invention
This invention relates to accumulating conveyor systems. More particularly, this invention relates to a lift and carry type of accumulating conveyor having a curved section between contiguous straight sections.
2. Description of the Prior Art
In an accumulating type conveyor, parts are advanced, usually in a single row, in a step by step manner. If it is necessary to direct the parts to a position transverse to a straight run of the conveyor section, the parts are often transfered to another conveyor. This involves the use of discharging and charging mechanisms with the added expense and complexities of the overall system. When there is sufficient floor space available, an arcuate or quarter circle conveyor segment has been successfully used. One such type conveyor using a long radius quarter turn section is disclosed is U.S. Pat. No. 4,838,411, owned by the common assignee of the present invention.
The conveyor of U.S. Pat. No. 4,838,411 utilizes a pair of elongated, spaced apart and parallel stationary rails. A pair of movable rails are located between the stationary rails which move from a point below to a point above the stationary rails, and from a retracted position to an advanced or forward position. Thus parts resting on the stationary rails are picked up by the movable rails and moved forward to a point where they are again lowered to a resting position on the stationary rails. This type of conveyor is particularly adapted for use in conveying conventional parts of various configurations which extend above the rails and also elongate parts which can extend between the rails. For example, automotive connecting rods can be conveyed with or without a cap attached to the beam while the beam extends between the rails, or the cap can be conveyed alone supported entirely above the rails.
When parts are being conveyed around a 90.degree. turn in this conveyor as shown in FIGS. 1, 11 and 11A of the patent, the oscillating motion imparted to the curved section has been isolated from the reciprocating motion of the two adjoining straight section which motions are at 90.degree. to each other. Since the invention of this patent was not directed to the curved conveyor section, per se, the details of the conveyor have not been shown. What has been shown in FIGS. 11 and 11A is that movable rails 34 are split at 86 at both ends of the curved section so that the movable rails in the curved section are separated from the movable rails in the two adjoining sections, and the rails 18 in the curved section pivot between an advanced position shown in FIG. 11A to a retracted position shown in FIG. 11. The only connection of moving parts between a straight section of the conveyor and the curved portion is for the transmission of motor power from the lifter assembly 70 of a straight section to the lift and carry assembly, not shown, for the curved section. With this type of separate actuation of the movable curved rails, the minimum radius turn achievable has been approximately 4'. This has been a minimum radius even with the use of guide rollers 92 and the like as schematically shown in FIGS. 10 and 10A of the patent. The size of the parts being conveyed have not contributed to this required large radius as a connecting rod may be of the order of 8" long with a maximum width of 4" at the crank shaft bearing end and a thickness of approximately 1".